x86/speculation/mds: Fix documentation typo
[linux/fpc-iii.git] / drivers / pci / search.c
blob4c6044ad7368acbe617fbd6bd90bfb359f29032a
1 /*
2 * PCI searching functions.
4 * Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
5 * David Mosberger-Tang
6 * Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz>
7 * Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
8 */
10 #include <linux/pci.h>
11 #include <linux/slab.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include "pci.h"
16 DECLARE_RWSEM(pci_bus_sem);
17 EXPORT_SYMBOL_GPL(pci_bus_sem);
20 * pci_for_each_dma_alias - Iterate over DMA aliases for a device
21 * @pdev: starting downstream device
22 * @fn: function to call for each alias
23 * @data: opaque data to pass to @fn
25 * Starting @pdev, walk up the bus calling @fn for each possible alias
26 * of @pdev at the root bus.
28 int pci_for_each_dma_alias(struct pci_dev *pdev,
29 int (*fn)(struct pci_dev *pdev,
30 u16 alias, void *data), void *data)
32 struct pci_bus *bus;
33 int ret;
35 ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), data);
36 if (ret)
37 return ret;
40 * If the device is broken and uses an alias requester ID for
41 * DMA, iterate over that too.
43 if (unlikely(pdev->dma_alias_mask)) {
44 u8 devfn;
46 for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) {
47 ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn),
48 data);
49 if (ret)
50 return ret;
54 for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
55 struct pci_dev *tmp;
57 /* Skip virtual buses */
58 if (!bus->self)
59 continue;
61 tmp = bus->self;
63 /* stop at bridge where translation unit is associated */
64 if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT)
65 return ret;
68 * PCIe-to-PCI/X bridges alias transactions from downstream
69 * devices using the subordinate bus number (PCI Express to
70 * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases
71 * where the upstream bus is PCI/X we alias to the bridge
72 * (there are various conditions in the previous reference
73 * where the bridge may take ownership of transactions, even
74 * when the secondary interface is PCI-X).
76 if (pci_is_pcie(tmp)) {
77 switch (pci_pcie_type(tmp)) {
78 case PCI_EXP_TYPE_ROOT_PORT:
79 case PCI_EXP_TYPE_UPSTREAM:
80 case PCI_EXP_TYPE_DOWNSTREAM:
81 continue;
82 case PCI_EXP_TYPE_PCI_BRIDGE:
83 ret = fn(tmp,
84 PCI_DEVID(tmp->subordinate->number,
85 PCI_DEVFN(0, 0)), data);
86 if (ret)
87 return ret;
88 continue;
89 case PCI_EXP_TYPE_PCIE_BRIDGE:
90 ret = fn(tmp,
91 PCI_DEVID(tmp->bus->number,
92 tmp->devfn), data);
93 if (ret)
94 return ret;
95 continue;
97 } else {
98 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
99 ret = fn(tmp,
100 PCI_DEVID(tmp->subordinate->number,
101 PCI_DEVFN(0, 0)), data);
102 else
103 ret = fn(tmp,
104 PCI_DEVID(tmp->bus->number,
105 tmp->devfn), data);
106 if (ret)
107 return ret;
111 return ret;
114 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
116 struct pci_bus *child;
117 struct pci_bus *tmp;
119 if (bus->number == busnr)
120 return bus;
122 list_for_each_entry(tmp, &bus->children, node) {
123 child = pci_do_find_bus(tmp, busnr);
124 if (child)
125 return child;
127 return NULL;
131 * pci_find_bus - locate PCI bus from a given domain and bus number
132 * @domain: number of PCI domain to search
133 * @busnr: number of desired PCI bus
135 * Given a PCI bus number and domain number, the desired PCI bus is located
136 * in the global list of PCI buses. If the bus is found, a pointer to its
137 * data structure is returned. If no bus is found, %NULL is returned.
139 struct pci_bus *pci_find_bus(int domain, int busnr)
141 struct pci_bus *bus = NULL;
142 struct pci_bus *tmp_bus;
144 while ((bus = pci_find_next_bus(bus)) != NULL) {
145 if (pci_domain_nr(bus) != domain)
146 continue;
147 tmp_bus = pci_do_find_bus(bus, busnr);
148 if (tmp_bus)
149 return tmp_bus;
151 return NULL;
153 EXPORT_SYMBOL(pci_find_bus);
156 * pci_find_next_bus - begin or continue searching for a PCI bus
157 * @from: Previous PCI bus found, or %NULL for new search.
159 * Iterates through the list of known PCI buses. A new search is
160 * initiated by passing %NULL as the @from argument. Otherwise if
161 * @from is not %NULL, searches continue from next device on the
162 * global list.
164 struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
166 struct list_head *n;
167 struct pci_bus *b = NULL;
169 WARN_ON(in_interrupt());
170 down_read(&pci_bus_sem);
171 n = from ? from->node.next : pci_root_buses.next;
172 if (n != &pci_root_buses)
173 b = list_entry(n, struct pci_bus, node);
174 up_read(&pci_bus_sem);
175 return b;
177 EXPORT_SYMBOL(pci_find_next_bus);
180 * pci_get_slot - locate PCI device for a given PCI slot
181 * @bus: PCI bus on which desired PCI device resides
182 * @devfn: encodes number of PCI slot in which the desired PCI
183 * device resides and the logical device number within that slot
184 * in case of multi-function devices.
186 * Given a PCI bus and slot/function number, the desired PCI device
187 * is located in the list of PCI devices.
188 * If the device is found, its reference count is increased and this
189 * function returns a pointer to its data structure. The caller must
190 * decrement the reference count by calling pci_dev_put().
191 * If no device is found, %NULL is returned.
193 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
195 struct pci_dev *dev;
197 WARN_ON(in_interrupt());
198 down_read(&pci_bus_sem);
200 list_for_each_entry(dev, &bus->devices, bus_list) {
201 if (dev->devfn == devfn)
202 goto out;
205 dev = NULL;
206 out:
207 pci_dev_get(dev);
208 up_read(&pci_bus_sem);
209 return dev;
211 EXPORT_SYMBOL(pci_get_slot);
214 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
215 * @domain: PCI domain/segment on which the PCI device resides.
216 * @bus: PCI bus on which desired PCI device resides
217 * @devfn: encodes number of PCI slot in which the desired PCI device
218 * resides and the logical device number within that slot in case of
219 * multi-function devices.
221 * Given a PCI domain, bus, and slot/function number, the desired PCI
222 * device is located in the list of PCI devices. If the device is
223 * found, its reference count is increased and this function returns a
224 * pointer to its data structure. The caller must decrement the
225 * reference count by calling pci_dev_put(). If no device is found,
226 * %NULL is returned.
228 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
229 unsigned int devfn)
231 struct pci_dev *dev = NULL;
233 for_each_pci_dev(dev) {
234 if (pci_domain_nr(dev->bus) == domain &&
235 (dev->bus->number == bus && dev->devfn == devfn))
236 return dev;
238 return NULL;
240 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
242 static int match_pci_dev_by_id(struct device *dev, void *data)
244 struct pci_dev *pdev = to_pci_dev(dev);
245 struct pci_device_id *id = data;
247 if (pci_match_one_device(id, pdev))
248 return 1;
249 return 0;
253 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
254 * @id: pointer to struct pci_device_id to match for the device
255 * @from: Previous PCI device found in search, or %NULL for new search.
257 * Iterates through the list of known PCI devices. If a PCI device is found
258 * with a matching id a pointer to its device structure is returned, and the
259 * reference count to the device is incremented. Otherwise, %NULL is returned.
260 * A new search is initiated by passing %NULL as the @from argument. Otherwise
261 * if @from is not %NULL, searches continue from next device on the global
262 * list. The reference count for @from is always decremented if it is not
263 * %NULL.
265 * This is an internal function for use by the other search functions in
266 * this file.
268 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
269 struct pci_dev *from)
271 struct device *dev;
272 struct device *dev_start = NULL;
273 struct pci_dev *pdev = NULL;
275 WARN_ON(in_interrupt());
276 if (from)
277 dev_start = &from->dev;
278 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
279 match_pci_dev_by_id);
280 if (dev)
281 pdev = to_pci_dev(dev);
282 pci_dev_put(from);
283 return pdev;
287 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
288 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
289 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
290 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
291 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
292 * @from: Previous PCI device found in search, or %NULL for new search.
294 * Iterates through the list of known PCI devices. If a PCI device is found
295 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
296 * device structure is returned, and the reference count to the device is
297 * incremented. Otherwise, %NULL is returned. A new search is initiated by
298 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
299 * searches continue from next device on the global list.
300 * The reference count for @from is always decremented if it is not %NULL.
302 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
303 unsigned int ss_vendor, unsigned int ss_device,
304 struct pci_dev *from)
306 struct pci_device_id id = {
307 .vendor = vendor,
308 .device = device,
309 .subvendor = ss_vendor,
310 .subdevice = ss_device,
313 return pci_get_dev_by_id(&id, from);
315 EXPORT_SYMBOL(pci_get_subsys);
318 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
319 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
320 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
321 * @from: Previous PCI device found in search, or %NULL for new search.
323 * Iterates through the list of known PCI devices. If a PCI device is
324 * found with a matching @vendor and @device, the reference count to the
325 * device is incremented and a pointer to its device structure is returned.
326 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
327 * as the @from argument. Otherwise if @from is not %NULL, searches continue
328 * from next device on the global list. The reference count for @from is
329 * always decremented if it is not %NULL.
331 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
332 struct pci_dev *from)
334 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
336 EXPORT_SYMBOL(pci_get_device);
339 * pci_get_class - begin or continue searching for a PCI device by class
340 * @class: search for a PCI device with this class designation
341 * @from: Previous PCI device found in search, or %NULL for new search.
343 * Iterates through the list of known PCI devices. If a PCI device is
344 * found with a matching @class, the reference count to the device is
345 * incremented and a pointer to its device structure is returned.
346 * Otherwise, %NULL is returned.
347 * A new search is initiated by passing %NULL as the @from argument.
348 * Otherwise if @from is not %NULL, searches continue from next device
349 * on the global list. The reference count for @from is always decremented
350 * if it is not %NULL.
352 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
354 struct pci_device_id id = {
355 .vendor = PCI_ANY_ID,
356 .device = PCI_ANY_ID,
357 .subvendor = PCI_ANY_ID,
358 .subdevice = PCI_ANY_ID,
359 .class_mask = PCI_ANY_ID,
360 .class = class,
363 return pci_get_dev_by_id(&id, from);
365 EXPORT_SYMBOL(pci_get_class);
368 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
369 * @ids: A pointer to a null terminated list of struct pci_device_id structures
370 * that describe the type of PCI device the caller is trying to find.
372 * Obvious fact: You do not have a reference to any device that might be found
373 * by this function, so if that device is removed from the system right after
374 * this function is finished, the value will be stale. Use this function to
375 * find devices that are usually built into a system, or for a general hint as
376 * to if another device happens to be present at this specific moment in time.
378 int pci_dev_present(const struct pci_device_id *ids)
380 struct pci_dev *found = NULL;
382 WARN_ON(in_interrupt());
383 while (ids->vendor || ids->subvendor || ids->class_mask) {
384 found = pci_get_dev_by_id(ids, NULL);
385 if (found) {
386 pci_dev_put(found);
387 return 1;
389 ids++;
392 return 0;
394 EXPORT_SYMBOL(pci_dev_present);